title: Purification of DNA topoisomerases and inhibition by fluoroquinolones.
abstract: Fluoroquinolones act by inhibiting the essential type II topoisomerases, DNA gyrase and topoisomerase IV (1). DNA gyrase is a tetramer composed of 2 A subunits and 2 B-subunits encoded for by gyrA and gyrB, respectively. This enzyme is the only enzyme known that is capable of negatively supercoiling DNA (2), a process essential for the bacterium to contain its DNA within the confines of the cell. Topoisomerase IV is also a tetramer composed of 2 C subunits and 2-E subunits encoded for by the parC and parE genes. This enzyme is involved in the unlinking of daughter chromosomes following replication (3).
authors.forename: G T
authors.initials: GT
authors.lastname: John
authors.forename: M
authors.initials: M
authors.lastname: Ian